This invention relates generally to closed containers, used industrially and commercially, to store and transport liquids and solids, and particularly to a container that replaces the standard 55-gallon drum.
Millions of 55-gallon drums have been used to store and transport liquids and solids. Their use, however, presents some problems that until now have been grudgingly accepted and accommodated.
A major problem has been the loss of transport and storage volume because the drums are cylindrical while warehouses, trucks and railroad cars are rectangular. Thus, even when the drums abut one another there is significant lost volume in the interstices between the drums. Generally, the weight of the drums and contained material is less than what the storage or transport space could safely carry so that the interstical space, which otherwise could contain more material, is just wasted. No acceptable container previously was available to take advantage of this unused space and the inefficiency was accepted.
Another significant problem with drums concerns their handling; drums are awkward and not readily handled by fork lift trucks. This problem has been accommodated by dedicating certain lift trucks to have special drum gripping devices or by providing special attachments for the tines of standard fork lift trucks. In either case, the drums are lifted only by either clamping around their sides or by clamping onto their top chimes or rims. Bottom lifting, without a skid, is impractical because of the cylindrical drum bottom not well mating with the long, narrow fork tines and the lack of access space under a drum. Bottom lifting also is impractical because drums inherently have a high center of gravity that makes them relatively unstable when upstanding. The special handling equipment and attachments operate satisfactory generally, but care must be exercised by operators to avoid crushing the drums during lifting and to avoid upsetting the drums during handling.
A further problem with drums concerns stacking. Drums have only top and bottom chimes or narrow rims extending from the side walls that are difficult to align closely for enabling the drums safely to be stacked one on top of another without shifting. The inherent instability of the drums, because of their high center of gravity, further contributes to the difficulty of stacking the drums safely.
It is known, see U.S. Pat. No. 3,942,670 to Mingus et al., to band four drums together and affix to the bottom of each drum a frusto-conical base plate having a single lift-tine receiving inverted U-shaped channel extending therethrough. The drums and base plate are arranged so that the U-channels form aligned passages for receiving the two parallel tines of a standard lift truck therethrough which can gain access to the drum in only one direction. The banded together four barrels then serve to stabilize one another when they are lifted from below by the lift truck. Additionally, when drums are stacked on one another, the conical base plates fit within the top rims of the underlying drums to stabilize same. This solution to the described problems is not believed practical, however, because four drums must always be banded together for the lift truck function to operate properly. One drum should not be lifted alone because of the instability rendered by its high center of gravity. Further, the drums easily can slip within the band to positions where the U-channels are misaligned.
An additional problem with 55-gallon drums is that the only access to the interior storage chamber of the drum is through the bung holes in the top wall or cover. Liquids must be pumped out of a standing drum, or a special carriage or cradle must be used safely to tip or rotate the drum to a horizontal position in which the liquid can be poured out of the drum. Removing solids from a drum present similar problems. Lastly, damaging a drum, which occurs easily, can easily result in the contained materials leaking out.
Designers of other drums and closed and open containers have attempted to solve some of these described problems associated with 55-gallon drums. U.S. Pat. No. 4,485,924 to Ripoll discloses an upright rectangular drum. A lower skirt, crimped to the bottom edge of the drum, defines an outwardly extending peripheral step that engages or mates with the rim of an underlying drum to pass the weight of a stacked drum to the sidewalls of a therebelow stacked drum. The skirt also includes four corner located feet that are suspended above the lid of the next lower drum when two drums are stacked on one another. Limited access to the opening in the lid of the drum is through centrally located openings on the sides of the skirt. No suggestion of lifting the drum with the tines of a lift truck is made in Ripoll, possibly because of the single, narrow centered opening in each side of the skirt and the high center of gravity thereof creating an unstable lifting condition. The Ripoll container is also more expensive to assemble than the present 55 gallon drum.
U.S. Pat. No. 3,547,299 to Kepple discloses a cube shaped closed container having four embossed side walls and top and bottom end plates welded to the peripheral, outwardly extending flanges of the side walls. The Kepple patent states that the cubic design facilitates lifting with a lift truck, but no structure is disclosed for accepting tines under the container and the disclosed lifting procedure is from above by chains and supplemental corner cleats. No structure is disclosed to prevent stacked containers from sliding off one another. Further, access to the container contents is through a recessed opening in the top plate that can easily be covered by an above stacked container.
There are many other patents for closed and opened containers that address one or some of the problems associated with 55-gallon drums, such as liftability, stackability and access to the contents. Those patents, however, fail to achieve the simplicity of design and manufacture of the present invention while overcoming the problems associated therewith.